Caseless ammunition for firearms and the like

ABSTRACT

There is herein disclosed caseless ammunition for firearms comprising a projectile portion and an associated caseless onepiece solid porous ungranulated propellant portion.

United States Patent {72] Inventor Jules Edmond Van Langenhoven BentonCounty, Ark. 121] App]. Nov 760,108 [22] Filed July 18, 1968 Division ofSer. No. 473,556, July 7, 1965 abandoned. [45] Patented May 11, 1971 1 73 Assignee Victor Comptometer Corporation Chicago, I11.

1 54 CASELESS AMMUNITION FOR FIREARMS AND THE LIKE 10 Claims, 6 DrawingFigs.

, 5 2] US. Cl 102/38, 102/101 '51] Int. Cl F42b 9/16 150] Field ofSearch102/38, 39, 43, 100, 101, (Cr Digest) 1 56] References Cited UNITEDSTATES PATENTS 35.949 7/1862 Potter 102/38 102/42 pub.

Maxim Hayner.. Hobbs Catlin et al. Galley eta1.... Johnson De Caro Heggeet a1. Dilchert FOREIGN PATENTS Italy OTHER REFERENCES SMOKELESSSI-IOTGUN POWDERS by Wallace H. Cox, pub. of E. I. DuPont Co. Inc.; pp.25 38; 1935 copy in Primary Examiner-Robert F. Stahl AttorneyHamess,Dickey and Pierce tion.

Patented May 11, 1971 4 Sheets-Sheet 3 INV R,

CASELESS AMMUNITION FOR FITKEARMS AND THE LIKE This invention relates tofirearm ammunition and, more particularly, to caseless ammunition foruse with various types of firearms including air operated projectilefiring apparatus. This application is a division of my copendingapplication Ser. No. 473,556 filed July 7, 1965, which is a continuationof my prior application Ser. No. 189,621 filed Apr. 23, 1962, nowabandoned.

SUMMARY OF INVENTION The present invention relates to caselessammunition for firearms. The illustrative embodiments of the inventioninvolve air operated .22 caliber firearms from which the ammunition isadapted to be fired as described in detail in the aforemention copendingapplication Ser. No. 473,556, filed July 7, I965. The caselessammunition is of generally cylindrical shape and comprises a projectileportion and a propellant portion of generally cylindrical shape. Thepropellant portion provides a one-piece solid porous ungranulatedpropelling charge of nitrocellulose. The projectile portion provides anintegral support means for the propellant portion which is locatedentirely internally of the cylindrical peripheral surface of theammunition. The projectile portion also provides holding and sealingmeans effective in a portion of the firing chamber of a firearm totemporarily axially hold the ammunition and to seal the bore end of thefiring chamber against the flow of gases into the bore from the firingchamber until after ignition and substantial burning of the propellant.

The principles of the present invention have been applied to ammunitionprojectile firing systems, devices, and apparatus as hereinafterdisclosed by reference to illustrative embodiments of the inventionshown on the accompanying drawings wherein:

H6. 1 is an enlarged sectional view of one form of ammunition;

FIG. 2 is an enlarged sectional view of a portion of firearm apparatusshown loaded with a round of ammunition of presently preferred form andin a firing position;

FIG. 3 is an enlarged side elevational view of a round of caselessammunition of the present invention;

FIG. 4 is an enlarged side elevational view of another round of caselessammunition of the present invention;

H6. 5 is an enlarged side elevational view, partly in section, of aportion of a stud-driving tool type of firearm stud-type round ofammunition in firing position; and

FIG. 6 is an enlarged side elevational view, partly in section, of analternative form of stud ammunition of the type shown.

While certain features of the present invention are particularly welladapted for use in air guns, it will be readily appreciated by thoseskilled in the art to which this invention relates that the inventiveprinciples are also applicable to other devices such as powder-actuatedtools. Also, while certain forms of the ammunition are particularlyadvantageous in certain applications, the projectile design and themanner of attaching the propellant thereto may be varied as necessaryand desirable depending upon such factors as the velocities required,breech pressure attained, the type of gun, and the projectile propellantcharacteristics.

A round of ammunition 110 adapted for use with a .22 caliber firearm orthe like comprises a lead mass projectile, or the like, having a frontend portion 112 and a rear end portion 114. In the illustrativeembodiment, the projectile is provided with an inwardly extending bore116. The rear end portion 114 is slightly outwardly flared as indicatedat 118 for abutting obturating engagement with a similarly contouredportion in the barrel bore of the firearm. The amount of taper isdependent upon the shot start force desired. The shot start force shouldbe sufficient to hold the projectile in place during the compressionstroke until the propellant is ignited. Bore 116 has a correspondinginwardly directed taper 119 as shown. The bore 116 provides a propellantstorage and ignition chamber within which one or more propellant caps120, 121 may be provided. ln the embodiment shown, a pair of spacedpropellant caps are illustrated. The propellant caps may comprise anitrocellulose produce which is ignitable under the effects of heat andpressure to create high energy. The caps have a disclike form which isreadily insertable into the bore 116. The caps have a diameter slightlysmaller than the open end of the bore 116 so that they may be pushedalong the tapered surface 119 of the bore until they are firmly wedgedin the ignition chamber provided thereby.

Although the caps may be made from any material which is adapted to bedecomposed at a high temperature to produce an explosive or gas-evolvingaction and which may be readily packaged, stored, and handled in areliable manner, exceptional results are obtained from a porous nitratedcotton product. Nitrocellulose is particularly well suited for this use.

With the aforedescribed nitrate cotton product, the caps are veryporous, easily ignited, completely burned upon ignition, and noundesirable residues are left in the barrel or the associated parts ofthe gun. While in most instances, the propellant may be manufactured,stored, and used in a solid stable form, it may be desirable, in somecases, to cover the propellant discs with a thin plasticlike film overthe entire periphery. The plasticlike film may take various forms and,for example, be provided by the nitrating solution itself.

The projectile is held in position by frictional engagement between theenlarged tapered portion 118 and the barrel. The propellant caps areignited by surface contact with the hightemperature air of the firingchamber and a high-level energy source is thereby provided forpropulsion. The projectile is driven from the barrel by compression ofthe enlarged flared portion 1 18 as the shot start force is reached.

FIG. 2 shows a portion of an illustrative firearm or gun having barrelobturation means comprising a chamfered section 273, formed at the endof a movable firearm member 228-adjacent to the barrel 223, which isadapted to form a lead-col lecting groove 274 and receive a beveled end275 of the barrel when the gun is in the firing position. A firstcylinder bore 276, corresponding to the barrel bore 224, is providedadjacent the chamfered section 273 and the opposite end of the bore 276terminates next to a larger diameter bore 277 joined by a beveledsection 278 which form projectile holding means as hereinafter describedin detail. Firing chamber obturation means are provided and comprise atapering obturation chamber 279 extending to the rear face of the rearface of the firearm member 228, adjacent a movable air compression unit233, 234, and terminating at its ends in a round 281 and a round 282.

The firing chamber obturation means further comprises obturator plugmeans 285 interposed between the air compression means and theammunition chamber 272. The obturator plug means comprises a generallycylindrically shaped housing 286 press fitted within a bore 287 formedin the cylinder head 233. The end of the obturator housing adjacent themember 228 is fomied with a tapered portion 288 that is complementary tothe tapering bore 279 in the member 228. An air passage 289 is formed inthe obturator housing and connects to a larger passage 291 formed inresilient disc 234 to provide airpassage delivery means by whichhigh-temperature air is delivered from the compression chamber.Obturator air passage 289 merges into a chamfered section 292 forming aseat for flow-control means in the form of a ball check valve 293. Inthe presently preferred form of the invention, the check valve 293 isfloatingly supported for movement within a bore 294 extending from thechamfered section 292 through the obturator housing 286. A colledretaining member 295 is positioned at the outer end of the bore 294 tofloatingly retain the ball check valve 293 within the bore. An enlargedchamber 296 is formed at the mouth of the bore 294 adjacent theretaining member 295. Caseless rounds of ammunition, indicated generallyby the reference numeral 301, and shown in detail in FlG. 2, are adaptedto be positioned within an ammunition chamber 272 of a firearm member228. 1n the presently preferred form of the invention, each round 301comprises a metallic (e.g. lead) slug haVING a generally cylindricalsection 302, complementary in diameter to the bore 277, and an endsection 303 adapted to extend into the bore 276. A beveled section 304,connecting sections 302 and 303. is adapted to abuttingly engage thebeveled section 278 of the projectile cavity 272 formed between the bore276 and 277 to axially position the round within the firing chamber inmember 228. The diameter of the cylindrical portion 302 is sufficientlylarger than the diameter of the bore 276 so as to form a seal betweenthe shoulders 278 and 304 and to hold the projectile in place in theammunition chamber until the propellant has been ignited and sufficientforce is obtained to compress the lead projectile and force it past theshoulder 278 and into the bore 276 and down the barrel bore 224. It isdesirable to have an arrangement providing a shot start force greaterthan the force obtained by compression of the air alone so that theprojectile will not start to move until after the propellant has beenignited. If a propellantless air-driven round of ammunition is to beused, the amount of frictional retention between the projectile and theammunition chamber is reduced greatly so that the ammunition is merelysupported in the ammunition chamber and is driven into the bores 224,276 as soon as or shortly after the compression stroke begins. In thismanner, the gun may be used as a high-velocity weapon with a round ofammunition having propellant associated therewith and a high-shot startforce, and may be used as a low-velocity air gun with a modified roundof propellantless ammunition having a low shot start force.

Propellant attaching means are provided in the form of a stub shaftportion 305, integrally connected to the cylindrical section 302, andterminating in a radially displaced upset por' tion 306. In thepresently preferred embodiment of the invention, a disc of solidpropellant 307, corresponding in diameter to a cylindrical section 302,is fixed to the stub shaft portion and held in place by upset portion306. While the presently preferred manner of associating the propellantwith the projectile provides particularly advantageous results, it iscontemplated that the propellant might be otherwise attached such as bydirectly bonding the propellant to the rear of the projectile withoututilizing the post 305. In the preferred embodiment, the length of thepropellant portion is approximately equal to the length of the mainportions of the projectile. The diameter and depth of the chamber 296are chosen so as to provide a minimum air gap and a minimum air volume.In the firing position. the high'temperature ignition air will beconfined in an ignition chamber defined by the ammunition, the walls ofthe ammunition chamber, the walls of the chamber 206, and the airpassage means extending from the valve seat 293. It will be apparentthat the ignition chamber is in effect also at least part of the firingchamber. The propellant 307 may be made up of a homogenous mass ofpropellant material or of several layers of different propellantmaterial each of which may be molded, extruded, or otherwise mounted onthe projectile. The layers may have successively higher ignition pointsprogressing toward the projectile to provide a greater thrust if sodesired or may be otherwise varied and modified to attain particularignition and firing characteristics.

In the presently preferred form of the invention, the propellant ismanufactured into a doughy mass suitable for formation in pellet or capforrn separately from the projectile or directly on the projectile. Thistype of ammunition is caseless and the entire round is fired from thegun without residue.

The propellant made in accordance with the practice of the presentinvention is formed into porous pellets containing as s essentialelements therein an ignitable explosive material and a cellulose bindermaterial.

The doughy mass may be molded onto the projectiles. The projectile, ofthe type shown in FIG. 2, is supported with a suitable die enclosing thestub shaft portion and forming a die cavity therearound approximatelyequal to the diameter of the projectile with suitable allowance forshrinkage and the like. The doughy mass is extruded into the die cavityaround the stub portion. The propellant dough is confined so that itcannot flow past the projectile and enough propellant dough is injectedto fill the die cavity and produce the desired length and diameterpellet when dry. A l,l00-feet-per-second formulation may be used incombination with a 1,200-feet-per-second formulation as an ignitioncharge as shown in FIG. 3. The main charge 3070 is extruded onto theprojectile first as hereinbefore described. Immediately thereafter, theprojectile and main charge are displaced slightly in the die means andthe ignition charge 30712 may be extruded into the rear of the maincharge. In the presently preferred form, shown in FIG. 3, the ignitioncharge is centrally placed in the rear of the main charge in a somewhatsemispherical form surrounded with and embedded in the main chargeexcept for an exposed rear surface.

In order to vary the velocity, it may be desirable to change the amountof propellant of any given formulation attached to the projectile.However, it is necessary and desirable to have the dimensions of theammunition remain constant. An inert charge may be first extruded ontothe projectile to occupy a portion of the volume of the normalpropellant cavity. An exemplary formulation for the inert chargecomprises:

grams talcum 5 grams hydroxyethyl cellulose (high viscosity) 30 gramswater A technical grade of talcum powder such as that sold by FisherScientific Company has been found to be satisfactory. This mixtureshould be kneaded into a doughy mass for approximately 30 minutes atroom temperature before being extruded. It is important that the inertdough have sufficient consistency to set up on the projectile withoutlending to flow past the projectile. In one illustrative arrangement,shown in FIG. 4, producing a velocity of approximately 700 feet persecond with the l,l00-feet-per-second propellant initially described, avolume of the inert charge 307C equal to the projectile diameter by .130long is molded onto the rear of the projectile. Then a quantity of thel,l00-feet-per-second propellant 307d equal to the projectile diameterby .090 long is molded onto the rear of the inert charge. This amount ofthe propellant will produce a velocity of approximately 700 feet persecond. The propellant material may be extruded in a tubular form. Forone type of propellant utilizing removable solid filler particles ofpotassium nitrate or the like to form the voids, a 0.250-inch nozzle anda 0.062-inch pin are utilized so that, after washing and drying, theoutside diameter of the propellant will be about 0.220 inches and theinside diameter will be about 0.045 inches. When the material has beendried, it is cut to lengths of about 0.l69 inches with a 0.010 wideslotting saw. A propellant pellet of approximately 157 mg. is thusprovided which, after washing, will weigh about 50 mg. After cutting,the removable filler is removed from the pelets by washing the pelletsfor approximately 4 days in slowly running water at about F. Thereafter,the propellant pellets are dried for approximately 24 hours and then thestill wet propellant may be pressed onto the post at the rear of theprojectile. It is to be understood that the propellant also may beextruded onto the projectile or molded thereon. In another methodutilizing removable liquid filler to form the voids the propellant is inthe form of a doughy mass ready for molding into a tubular form forsubsequent association with the projectile or for direct molding ontothe projectile as hereinbefore described. After the molded pellets havebeen at room temperature for about 5 minutes, they are boiled in a2-kpercent potassium nitrate water solution for approximately 15 minutesand are then dried at l40 F. Boiling of the pellets in the KNO -watersolution reduces shrinkage and increases the rate of removal of thesolvents to produce the voids in the propellant. Consequently, nofurther rinsing is required and the remaining KNO will act as anoxidizing agent during burning of the propellant.

Advantages of these propellants are that they may be economicallymanufactured, they are stable both in manufacture and use under normalconditions, they may be easily associated with a projectile to formcaseless-type ammunition, and they will burn cleanly and minimizecorrosion of the gun parts. Furthermore, while being stable and harmlessin asscciation with a projectile during manufacture, storage, andhandling, when properly positioned in a firing chamber of a gun, theyare capable of being ignited and generating highenergy gases, which whenproperly confined, are capable of propelling a projectile through a gunbarrel at high velocity. While the propellant attached to the projectilecan be ignited in the open by a flame from a match or the like, thepropellant merely bums at a slow rate causing no movement of theprojectile and is completely harmless. In addition, the propellants andthe methods of making them provide versatility and flexibility to enablepropellants of varying degrees of porosity to be obtained in a mannerwhich is simpler and more economical than previously known.

In an air ignition system, the ammunition is associated with firingchamber means of a firearm and connected to hot air ignition means inthe form of an air compression cylinder as shown in FIG. 2.

Air under increased pressure and temperature enters the ignition chamberthrough the passages 289, 291. The ball valve depending upon its initialposition, is either forced away from the valve seat or maintained awayfrom the valve seat by the high-pressure air and the flow passagebetween the ignition chamber and the compression chamber is kept openuntil the pressure in the ignition chamber becomes greater than thepressure in the passages 289, 291 due to leakage of air past the pistonat the end of the compression stroke. When the pressure differential isattained, the ball valve 293 is moved onto the valve seat 292 and thepassage 289 is closed. It has been found that ignition of the propellantwill ordinarily occur after the valve is closed due to an ignition timedelay apparently equal to the time necessary to transfer heat from theair to the propellant and raise the temperature of the propellant to theignition temperature. The front of the ammunition round 301 provides aseal in the bore 277 and on the shoulder 278 so that thehigh-temperature ignition air cannot leak past the round. When the roundbegins to move, lead on the projectile portion 302 is compacted topermit movement past shoulder 278 and, as the projectile moves into thebarrel, it has been found that some of the lead will be removed from theprojectile and forced into the lead-collecting groove 274. Consequently,upon subsequent firings, there will be an accumulation of lead in thegroove and a lead seal will be established between the barrel and thecylinder. The high-temperature of the air within the ignition chamberignites the propellant 307 and the projectile 301 is driven out of thebarrel bore 224 at a high velocity. The ball check valve 293 is drivenagainst its seat 292 so that the products of ignition will not enter theair compression cylinder 29] through passages 289, 291.

Referring now to FIGS. 5-6, certain of the inventive principles areshown to be embodied in ammunition for a powderactuated stud-drivingtool.

Referring again to FIGS. 5-6, the projectile to be driven from the toolmay take any of the conventional forms now available for use in tools ofthis general type. ln the illustrative embodiment, the round ofammunition 730 comprises a projectile portion in the form of a studhaving an elongated shank portion 732, terminating in a pointed end 733,and a headed portion 734. A propellant portion of the round ofammunition comprises, in the illustrative embodiment, plug means 736attached to the projectile head portion and providing support means 738,obturation shoulder means 740, and propellant attaching means 742. Theplug means may be made of any suitable material. such as plasticmaterials, which will be capable of being compressed and driven throughbore 608 in the barrel 676 after ignition of the propellant. In theillustrative embodiment, the propellant 744 is mounted in a cavity atthe rear of the plug with a surface exposed for surfacecontact withhightemperature air delivered from a hot air source to the firingchamber formed between a rearwardly movable breech member 694 andchamber surfaces 692, 693 at the rear of the tool barrel 676 throughpassage 706. It will be understood that the propellant may be otherwiseattached or associated with the projectile. Referring now to FIG. 6, analternative projectile form is shown to comprise a threaded head portion748 with the plug means 736 being generally cylindrical and molded orextruded onto the threaded head portion as shown. The barrel may bemodified as necessary or desirable by, for example, providing anobturation shoulder for engagement with the surface 750 as hereinbeforedescribed in regard to the ammunition shown in FIG. 2. lt will beunderstood that any other stud form may be utilized and, as isconventional, a guide ring 746 may be mounted on the front of the studs.

It will be apparent that the aforedescribed tool operates similarly tothe aforedescribed gun apparatus. In the firing position, it will beobserved that the propellant cap 744 is exposed in the firing chamberfor contact with high-temperature air to be delivered from the aircompression means during firing of the tool while the front edge of theplug 736 also serves to hold the stud in the barrel until the time thatthe propellant is ignited and the stud is driven down the barrel.

While the propellant is shown to be attached to the stud, it could beseparately loaded. Furthermore, while in the illustrative embodiment, afree-flight powder-actuated tool is disclosed, certain principles ofthis invention are applicable to a piston-driven-type tool as will bereadily understood by those skilled in the powder-actuated-tool art.

In the broadest aspects of the present invention it is contemplated thatother types of propellant may be used and that other propellant ignitionmeans may also be provided. However, particularly advantageous resultsare obtained by the use of the particular propellant and the particularmeans of igni tion the propellant disclosed. Obviously, the details ofconstruction and the arrangement of the parts may be varied withoutdeparting from the principles herein disclosed. Since the inventiveprinciples disclosed herein have obvious application in alternativecombinations, it is intended that the scope of this invention as definedby the appended claims include those alternative embodiments whichutilize the inventive principles herein disclosed.

lclaim:

l. A round of caseless ammunition having a generally cylindricalperipheral surface and shape comprising only a onepiece integralprojectile and a one-piece integral attached propellant charge:

the projectile comprising a generally rounded variablediameter noseportion;

a cylindrical center portion of larger diameter'than the nose portion;

a cylindrical support surface on said projectile for supporting theammunition in a firing position in a firing chamber in a firearm;

a transverse annular forwardly facing shoulder means on said projectilefor temporarily holding the ammunition against axial displacement andsealing the ammunition on a corresponding shoulder means in a firingposition in a firing chamber in a firearm;

a tail portion of reduced size relative to the cylindrical centralportion;

the propellant charge comprising one relatively large homogeneous poroussolid ungranulated colloided piece of nitrocellulose having a size andshape generally corresponding to the cylindrical central portion of theprojectile and forming a rearwardly extending continuation thereof andmounted on and permanently attached thereto by attachment meansincluding said tail portion of the projectile, said attachment meansbeing located completely internally of the generally cylindricalperipheral surface of the round of ammunition.

2. The invention as defined in claim 1 and said tail portion comprisinga reduced-diameter support post means centrally protruding from the rearof said projectile and being of reduced diameter relative to saidpropellant charge and being centrally embedded in said propellantcharge.

3. The invention as defined in claim 2 and wherein said support postmeans includes radially extending portions providing flange meansaxially locating said propellant charge relative to said projectile.

4. The invention as defined in claim 1 and said propellant charge havinga cylindrical peripheral side surface and a transverse rear end surfacewhich by themselves form the entire outer peripheral surfaces of therear portion of the ammunition.

5. The invention as defined in claim 1 and having an ignition chargeattached to said propellant charge.

6. The invention as defined in claim 5 and said ignition charge beingembedded in the rear end of said propellant charge.

7. A round of ammunition for a powder-actuated tool or the likecomprising a projectile and a caseless porous solid propellantassociated therewith, said projectile comprising a head portion at therear thereof and an elongated shank portion extending forwardly fromsaid head portion, the shank portion being smaller than the bore withwhich the projectile is to be associated for firing, guide and supportmeans mounted on said shank portion and on said head portion and beinglarger than the shank portion and the head portion and of a similar sizeas the bore with which it is to be associated for firing, andpropellant-attaching means provided on said guide and support means, thepropellant being attached to the guide and support means.

8. The invention as defined in claim 7 and said propellantattachingmeans comprising a rearwardly extending cavity.

9. The invention as defined in claim 8 and 'said rearwardly extendingcavity being formed in said guide and support means rearwardly of saidhead portion.

10. The invention as defined in claim 7 and shoulder means formed onsaid propellant-attaching means for abutting engagement with said bore.

1. A round of caseless ammunition having a generally cylindricalperipheral surface and shape comprising only a one-piece integralprojectile and a one-piece integral attached propellant charge: theprojectile comprising a generally rounded variable-diameter noseportion; a cylindrical center portion of larger diameter than the noseportion; a cylindrical support surface on said projectile for supportingthe ammunition in a firing position in a firing chamber in a firearm; atransverse annular forwardly facing shoulder means on said projectilefor temporarily holding the ammunition against axial displacement andsealing the ammunition on a corresponding shoulder means in a firingposition in a firing chamber in a firearm; a tail portion of reducedsize relative to the cylindrical central portion; the propellant chargecomprising one relatively large homogeneous porous solid ungranulatedcolloided piece of nitrocellulose having a size and shape generallycorresponding to the cylindrical central portion of the projectile andforming a rearwardly extending continuation thereof and mounted on andpermanently attached thereto by attachment means including said tailportion of the projectile, said attachment means being locatedcompletely internally of the generally cylindrical peripheral surface ofthe round of ammunition.
 2. The invention as defined in claim 1 and saidtail portion comprising a reduced-diameter support post means centrallyprotruding from the rear of said projectile and being of reduceddiameter relative to said propellant charge and being centrally embeddedin said propellant charge.
 3. The invention as defined in claim 2 andwherein said support post means includes radially extending portionsproviding flange means axially locating said propellant charge relativeto said projectile.
 4. The invention as defined in claim 1 and saidpropellant charge having a cylindrical peripheral side surface and atransverse rear end surface which by themselves form the entire outerperipheral surfaces of the rear portion of the ammunition.
 5. Theinvention as defined in claim 1 and having an ignition charge attachedto said propellant charge.
 6. The invention as defined in claim 5 andsaid ignition charge being embedded in the rear end of said propellantcharge.
 7. A round of ammunition for a powder-actuated tool or the likecomprising a projectile and a caseless porous solid propellantassociated therewith, said projectile comprising a head portion at therear thereof and an elongated shank portion extending forwardly fromsaid head portion, the shank portion being smaller than the bore withwhich the projectile is to be associated for firing, guide and supportmeans mounted on said shank portion and on said head portion and beinglarger than the shank portion and the head portion and of a similar sizeas the bore with whIch it is to be associated for firing, andpropellant-attaching means provided on said guide and support means, thepropellant being attached to the guide and support means.
 8. Theinvention as defined in claim 7 and said propellant-attaching meanscomprising a rearwardly extending cavity.
 9. The invention as defined inclaim 8 and said rearwardly extending cavity being formed in said guideand support means rearwardly of said head portion.
 10. The invention asdefined in claim 7 and shoulder means formed on saidpropellant-attaching means for abutting engagement with said bore.